An advanced wireless access method of cellular mobile communication and wireless network (hereinafter referred to as “Long Term Evolution (LTE)” or “Evolved Universal Terrestrial Radio Access (EUTRA)” is under discussion by 3rd Generation Partnership Project (3GPP).
In LTE, orthogonal frequency division multiplexing (OFDM) is used as a communication method in a downlink (DL) wireless communication from a base station apparatus to a mobile station apparatus.
As for a communication method for uplink (UL) wireless communication from a mobile station apparatus to a base station apparatus, single-carrier frequency division multiple access (SC-FDMA), which is a single-carrier transmission method, is used.
(LTE Radio Frame Format)
The format of a LTE radio frame is classified into Type 1 for a frequency division duplex (FDD) mode and Type 2 for a time division duplex (TDD) mode.
In each of these two modes, one radio frame includes 10 subframes, and one subframe includes two slots. One subframe includes a plurality of physical resource blocks (PRB). One physical resource block PRB includes 12 OFDM subcarriers (SC) disposed along a frequency axis and one slot which is a set of OFDM symbols disposed along a time axis.
A plurality of physical resource blocks PRB are contiguously disposed along the frequency axis. One physical resource block PRB includes a plurality of resource elements RE. One resource element RE includes one OFDM subcarrier SC along the frequency axis and one OFDM symbol along the time axis. A detailed description thereof may be founded, for example, in NPL 1, and thus a further description thereof is omitted here.
(LTE Relay Technology)
LTE uses a relay technology for expanding a service area, supporting a hot spot, handling a low-quality radio coverage, or the like. FIG. 17 is a diagram illustrating the LTE relay technology.
As illustrated in FIG. 17, mobile station apparatuses (user equipment) UE 1a to 1c communicate with relay station apparatuses 2a to 2c called relay nodes RN, while the relay station apparatuses 2a to 2c communicate with a main base station apparatus DeNB (Doner eNodeB) 3a. 
The relay station apparatuses 2a to 2c are wirelessly connected to the main base station apparatus 3a via a wireless backhaul links (Un interface) 4a to 4c, and the mobile station apparatuses 1a to 1c are connected to the relay station apparatuses 2a to 2c via radio access links (Uu interface) 5a to 5c. 
The main base station apparatus 3a provides not only a relay connection to a plurality of relay station apparatuses 2a to 2c but it is also capable of directly communicating with the mobile station apparatus 1d via a radio access link 5d without using a relay connection. A detailed description thereof may be founded, for example, in NPL 2, NPL 3, or the like, and thus a further description thereof is omitted here.
(Configuration of LTE Physical Channel)
FIG. 18 is a diagram illustrating a configuration of LTE physical channels. As illustrated in FIG. 18, the base station apparatus 3a and the mobile station apparatus 1d are connected to each other via the radio access link 5d. The radio access link 5d includes a plurality of LTE physical channels.
The LTE physical channels include physical downlink channels in a downlink used to transmit information from the base station apparatus 3a to the mobile station apparatus 1d and physical uplink channels in an uplink used to transmit information from the mobile station apparatus to the base station apparatus.
The physical downlink channels include downlink reference signals (DLRS), synchronization signals (SS), a physical broadcast channel (PBCH), a physical downlink control channel (PDCCH), a physical downlink shared channel (PDSCH), a physical multicast channel (PMCH), a physical control format indicator channel (PCFICH), and a physical hybrid automatic repeat request (HARQ) indicator channel PHICH.
The physical uplink channels include uplink reference signals (ULRS), a physical uplink control channel (PUCCH), a physical uplink shared channel (PUSCH), and a physical random access channel (PRACH). A description of detailed configurations and functions of respective physical channels may be found, for example, in NPL 2 or other LTE specifications, and thus a further description thereof is omitted here.